PENSACOLA, Fla., Dec 7 (Reuters) - The Saudi airman accused of killing three people at a U.S. Navy base in Florida appeared to have posted criticism of U.S. wars and quoted slain al Qaeda leader Osama bin Laden on social media hours before the shooting spree, according to a group that tracks online extremism.

Federal investigators have not disclosed any motive behind the attack, which unfolded at dawn on Friday when the Saudi national is said to have begun firing a handgun inside a classroom at the Naval Air Station Pensacola. U.S. Defense Secretary Mark Esper said during a public appearance on Saturday he was not ready to label it an act of terrorism.

A vigil was held on Saturday for those wounded and killed, among them a recent Naval Academy graduate who dreamed of being a fighter pilot and a teenage Arab American.

A sheriff's deputy fatally shot the gunman, authorities said, ending the second deadly attack at a U.S. military base within a week. Within hours, Saudi Arabia's King Salman had called U.S. President Donald Trump to extend his condolences and pledge his kingdom's support in the investigation.

Authorities confirmed the suspect was a member of the Royal Saudi Air Force who was on the base as part of a U.S. Navy training program designed to foster links with foreign allies. In an emailed statement on Saturday, the FBI named him as Second Lieutenant Mohammed Saeed Alshamrani, 21.

The young officer was reported to have played videos of mass shootings at a dinner earlier in the week with other Saudi aviation students, according to U.S. media reports on Saturday that cited an unnamed person briefed on the investigation.

Investigators have found no sign Alshamrani had links to international terrorist groups and think he may have radicalized on his own, the New York Times reported, citing an unidentified U.S. official. It said the airman first entered the United States in 2018, returned to Saudi Arabia, then re-entered the United States in February, and had reported for training at the base about three days before the attack.

At least three of the eight people wounded were law enforcement officers shot as they responded to the attack, officials said, including one Navy police officer and two county sheriff's deputies. They were expected to recover.

One of the dead was identified earlier Saturday by relatives as Joshua Kaleb Watson, 23. A recent graduate of the Naval Academy in Annapolis, Maryland, he had arrived at Pensacola two weeks ago for flight training, his family said.

"Joshua Kaleb Watson saved countless lives today with his own," Watson's brother, Adam Watson, wrote on Facebook on Friday. "After being shot multiple times he made it outside and told the first response team where the shooter was and those details were invaluable."

The Navy, in an emailed statement, named the other victims as Mohammed Sameh Haitham, 19, and Cameron Scott Walters, 21, both sailors studying at the base.

A cousin of Sameh, Hani bin Ali Moqbel, wrote on Twitter: "God have mercy on you Mohammed, and ease your parent's pain after your loss. May you rest in heaven (We belong to Allah and to Him we shall return.)"

OTHER SAUDIS QUESTIONED

In comments to reporters at the White House on Saturday, Trump said the Saudi king and crown prince were "devastated" by what took place, and that the king "will be involved in taking care of families and loved ones."

"I think they're going to help out the families very greatly," Trump said.

Six other Saudi nationals were being questioned by investigators in Florida, three of whom were seen filming the incident, the New York Times reported, citing an unidentified person briefed on the investigation.

An uncle of Alshamrani, Saad bin Hantim Alshamrani, told CNN from Saudi Arabia that his nephew was "likable and mannered towards his family and the community." He said his nephew "has his religion, his prayer, his honesty and commitments."

The younger Alshamrani appeared to have posted a justification of his planned attack in English on Twitter a few hours before it began, according to SITE Intelligence Group, which monitors online Islamist extremism.

He referred to U.S. wars in Muslim countries, writing that he hated the American people for "committing crimes not only against Muslims but also humanity," and criticizing Washington's support for Israel, SITE's analysis said. He also quoted bin Laden, the Saudi mastermind of the attacks on the United States on Sept. 11, 2001, according to SITE.

Reuters has not verified the authenticity of the account, @M&MD_SHAMRANI, which was suspended by Twitter on Friday.

GLASS AND BLOOD

About 100 people gathered at the Olive Baptist Church for a vigil on Saturday, where Chip Simmons, chief deputy in the Escombia County Sheriff's office, recounted being one of the first on the scene, which he said was littered "with glass and blood, with killed and wounded lying on the floors."

"You realize in that moment that you are witnessing loss of life and hatred, but there was also heroism," Simmons said.

The base outside Pensacola, near Florida's border with Alabama, is a major training site for the Navy and employs about 16,000 military and 7,400 civilian personnel, according to its website.

On Wednesday, a U.S. sailor shot three civilians at the historic Pearl Harbor military base in Hawaii, killing two of them before taking his own life.

Military personnel are normally restricted from carrying weapons on U.S. bases unless they are part of their daily duties, a policy designed to reduce the risk of suicides and accidental shootings. (Reporting by Brad Brooks in Pensacola and Jonathan Allen in New York; Additional reporting by Andrew Hay, Phil Stewart, Jan Pytalski, David Brunnstrom, Idrees Ali and Nayera Abdallah; Writing by Jonathan Allen; Editing by Daniel Wallis)